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Sound laws · Law 14 · Consonants

L before a consonant becomes u

L + consonant

Spanish

al → o (otro); ult → uch (mucho); often kept

French

l → u, fused with the vowel: au [o], ou [u], eau

Italian

l kept (altro, caldo)

Portuguese

al → ou, oi in some words (outro, foice); written l elsewhere, said [w] in Brazil

Romanian

l kept (alt, cald)

Catalan

l kept (altre, falç)

What happened

Before a consonant, l was 'dark': the back of the tongue rose toward the soft palate, close to a w. French turned it fully into u, which merged with the vowel before it (al → au → [o], ol → ou → [u], el → eau). Spanish and Portuguese did this only in a few words: al + consonant became o in Spanish, ou or oi in Portuguese (otro, outro; hoz, foice), and ult became uch in Spanish (mucho, escuchar). Italian, Romanian and Catalan kept the l; Brazilian Portuguese has since vocalized every syllable-final l in speech (alto [ˈawtu], Brasil [bɾaˈziw]).

Examples

LatinItalianSpanishFrenchPortugueseRomanianCatalanEnglish relative
ALTERUM‘other’altrootroautreoutroaltaltrealter
FALCEM‘sickle, scythe’falcehozfauxfoice—falç
AUSCULTĀRE (VL *ASCULTĀRE)‘to listen’ascoltareescucharécouterescutarascultaescoltarauscultation
CULTELLUM‘knife (pt cutelo 'cleaver')’coltellocuchillocouteaucutelo—coltell
CALIDUM (VL CALDUM)‘hot (es, pt caldo 'broth')’caldocaldochaudcaldocald—
PALMAM‘palm’palmapalmapaumepalmapalmăpalmapalm

Decoder

French au, ou before a consonant often hide an l: autre → altro, alt, altre; chaud → caldo, cald; couteau → coltello. Spanish uch can hide ult (escuchar → ascoltare), and Portuguese ou, oi an al (outro, foice).

Exceptions

Before a vowel French keeps the l, which explains pairs like cheval/chevaux, bel/beau, nouvel/nouveau, fol/fou. Spanish and Portuguese mostly kept l (alto, alba, Spanish dulce), and learned words keep it everywhere (altérer, falsifier, alternativa). Catalan calent 'hot' comes from CALENTEM, not CALDUM.

Watch it happen: CASTELLUM

In your word bank